Accuracy and predictive features of FDG-PET/CT and CT for diagnosis of lymph node metastasis of T1 non-small-cell lung cancer manifesting as a subsolid nodule.

Abstract

To retrospectively evaluate the diagnostic accuracy and predictive features of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG-PET/CT) and CT in lymph node (LN) staging of T1 non-small-cell lung cancers (NSCLCs) manifesting as subsolid nodules. From January 2005 to May 2011, 160 patients with pathologically proven T1 subsolid NSCLCs with LN staging were included in this study. Diagnostic accuracies of FDG-PET/CT and CT for LN staging were evaluated. Maximum standardised uptake value (SUVmax) and CT features of primary tumours were evaluated to investigate predictive factors for LN metastasis. LN metastases were found in nine of the 160 patients (5.6%). No LN metastasis was present in patients with a solid proportion ≤50%. Sensitivity, specificity and accuracy of FDG-PET/CT for LN staging on a per-patient basis were 11.1%, 86.1% and 81.9%; those of CT were 11.1%, 96.7% and 91.9%. Among patients with a solid proportion >50%, there were significant differences in SUVmax, solid portion size, solid proportion and lesion location between patients with and without LN metastasis. Multivariate analysis revealed that higher SUVmax, a larger solid proportion and central location were independent predictors of LN metastasis. FDG-PET/CT adds little value to CT in the lymph node staging of T1 subsolid NSCLCs. Lymph node (LN) metastases are important in non-small-cell lung cancer (NSCLC). • Positron emission tomography (PET) helps to stage solid NSCLCs. • FDG-PET/CT adds little to the LN staging of T1 subsolid NSCLCs. • No LN metastasis in patients with a solid proportion ≤50%. • LN metastasis is more common in solid and/or centrally sited tumours.